Manchester United fans are always eager to see Cristiano Ronaldo performing his signature "Siu" goal celebration. Unfortunately, the very same moment may have cost the player dearly, after it was reported that he injured himself after one such over zealous celebration during their recent victory against Arsenal.

On Thursday, the football world was abuzz after Ronaldo scored a brace to rescue the Red Devils against the Gunners. It was a come-from-behind 3-2 win, with Ronaldo sealing the victory through a penalty in the 70th minute. After finding the back of the net, he ran straight to the corner post as expected, where he leapt up in the air to land square on both feet with his hands swinging down on either side as he shouted "siuuuuuuuuuuu!" in unison with a roaring crowd.

According to Marca, the goal celebration may have resulted in a knee injury. It was not immediately obvious that the 36-year-old had hurt himself, but he wobbled off in the 88th minute clearly uncomfortable. Now, it is believed that he may be in doubt for the arrival of new manager Ralf Rangnick. The German will be taking the reins at Old Trafford, and he may not have his star player available on his debut.

Rangnick's style in not perceived to suit Ronaldo, but the German has assured that he is open to adjusting based on the players that are at his disposal. "You always have to adapt your style or your idea of football to the players you have available, not vice-versa," he said, adding words of admiration directed at the five-time Ballon d'Or winner. "Having seen Cristiano against Arsenal in the second half, at the age of 36 he is an amazing top professional."

There is no doubt that Ronaldo is still physically fit, and the manager believes that he won't have any problems motivating the number 7 to work hard. However, he pointed out that the rest of the squad need to step up as well. "We play in the most competitive league in the world so we need all the players on board. From what I saw from Cristiano, he is more than willing to do that, to put his input into the team. His teammates will have to do the same," said Rangnick.

Cristiano Ronaldo
801 not out: Cristiano Ronaldo took his career tally for club and country to 801 with a double against Arsenal AFP / Oli SCARFF